I have an A/C issue with my 1999 BMW 323i. Cold air would not blow through the vents unless I drove the car (or revved the engine) to about 2K RPM's. Once on the road the A/C seemd to be fine. However, at times the cold air would stop working and only outside air would come through the vents.A month ago I took my car to my local BMW dealershp and they replaced the pump (condenser unit)? This seemed to work for a short while. I'm noticing again that when I start my car and sit at idle, cold air is again not coming through the vents. When I get on the road, cold air is blowing again. Note: For grins I tried to put the heat on while idling. Only outside air came through the vents, the air was not hot. Only when I revved the engine did the hot air start blowing.The mechanic said that the clutch seemed to be working fine and that my problem was the pump. Any help would be appreciated. Thanks.
Engine: 3.0 6 cylinder
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Can I have the last 7 digits of your VIN #
Which one is it?
Give me 1 moment and I will get right back to you.
Ok. Miles on my car: 116K
Another note: The dealership took 2 days to determine that I needed a new condenser unit. I didn't get the sense that the mechanic was as qualified as he should have been. It almost seemed that he was guessing at the issue.
I am going to switch us over from Chat to Q&A this way I can post some pictures, if it states I disconnected just ignore that. I am still here and you will be able to continue as normal. Let me know when you are ready.
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It does sound as if he was guessing.
I am still here but will be typing an explanation which might take a few minutes
The a/c system uses 2 separate fans during normal operation. The 1st 1 is used either with or without the a/c on, and this is the fan which I am leaning towards being your problem. Let me explain:
This fan is controlled by what is called a fan clutch and it is used to cool the radiator during normal operation, when the temperature reaches a certain temperature in front of the radiator this fan clutch has a bi-metallic strip which will expand or contract depending on temperature. When it is heated in will close off a chamber in the fan clutch will will make it go from the fan just free wheeling to the fan locking up and when it locks up it cools down the area in front of the radiator. It works this way to save on fuel and engine load that is why it is not engaged all the time. Over time the oil that is inside of the fan clutch will leak out and the fan clutch will not lock up fully.
In order for the a/c to be efficient at idle it uses this fan and the other fan which is called the auxiliary fan to remove the heat from in front of the a/c condenser and the radiator. As long as this heat is not being removed it will blow warm or hot air from the vents.
And once you are driving the airflow will remove the heat this is why it cools down when you drive and it works normal. And when you rev it up to 2000 rpm's at idle there might be enough oil left in the fan clutch to engage the fan just enough to remove some heat.
So you will need to have the fan clutch checked for proper operation and also the auxiliary fan. Most likely you will need to replace the fan clutch.
If I have answered your question I ask that you please accept.
BMW Master Technician over 20 years BMW Dealership Experience. BMW Auto Repair Shop Business Owner
That makes sense. Any idea on cost to replace the fan clutch?
Yes I can give you the part # XXXXX with the prices, but since I answered you original question you would need to accept my answer. And then I would be more then happy to answer any follow up questions.
I will always leave positive feedback all I ask is for the same.
Thank you very much give me a few moments to look everything up and I will get right back to you.
Item # XXXXX is the Fan Clutch in the diagram. Depending on your dealership the average labor time to replace it is 1.0 hour. The price below for the part is a national average so your dealers price may vary.